Further to our earlier article on how to soundproof a room this article will deal more with creating a home studio or home cinema that is becoming more popular today.
First of all it is rarely possible to achieve complete soundproofing in a house or flat but the following will help you achieve the best soundproofing possible to enable you to enjoy your new studio or cinema. Most modern buildings are constructed from lightweight materials that are extremely inefficient at blocking sound and also allow sound to “flank” through the structure to other rooms. This flanking noise is very difficult to address 100% and is noise that can still be heard several rooms away from where the noise is being generated so it is important to design and build your soundproofed room properly.
Most of you will have heard of the concept “a room within a room” and this is the best way to proceed. Basically. A room within a room is exactly what it says, an independent room built inside another already existing room regardless of the structure of the existing room. But having said that, it is often important to upgrade the existing room first to ensure that you achieve the maximum soundproofing benefit. So first of all we will start with the floor and ceiling assuming they are timber suspended (timber joist supported).
Because these are usually the lightest part of a home’s structure, they should be upgraded acoustically to minimise the amount of noise that would otherwise penetrate them so the following will describe the maximum that you can do. Anything less, of course will be reflected in the overall result.
If the ceiling is lathe and plaster, whatever you do, DO NOT REMOVE IT! But upgrade it with an additional layer of 15mm high density Acoustic Plasterboard screwed up with our 1mm SoundBlocker Membrane sandwiched between the old ceiling and the new plasterboard. Then lift the flooring above and insert as a loose infill 100mm of AMW100 Acoustic Mineral Wool or for an enhanced result and if budget allows, fit our SoundBlocker Quilt. If the ceiling is just plasterboard then this can come down so that a new ceiling can be decoupled from the joists using our Resilient Bar system. These are 15mm deep thin steel bars that are screwed across the underside of the joists. Then before fitting 30mm (2 x 15mm) of Acoustic Plasterboard screwed to the bars, loosely fit between the joists and resting on top of the bars the AMW100 mentioned earlier. For an enhanced result, the SoundBlocker Membrane can again be sandwiched between the layers of plasterboard. And here is a tip. Don’t try to glue the membrane to the ceiling because you will find it extremely difficult but simply glue it using our Sta-Put special aerosol contact adhesive to the second layer of plasterboard before screwing it to the first layer already fixed. For more information on how to fix the Resilient Bar system, go to our installation instructions.
Here we will assume you do not have access to the ceiling below but if you do then follow the instructions in the above paragraph. First you should lift the floorboards and install 100mm of AMW100 between the joists as a loose fit. It is often thought that the AMW should be tight fit with no gaps but this is not true because the AMW is a sound absorber not a sound barrier. The reason it is between the joists is to soak up the sound that would otherwise reverberate and amplify noise entering the voids and can make an improvement of around 2dB on its own. If budget allows then the AMW can be substituted with our SoundBlocker Quilt which is both a sound absorber and sound barrier mat so is important that this product is fixed to the sides of the joists so that air leakage around the quilt is minimised. Before replacing the floorboards, SoundBlocker Membrane can also be fitted across the top of the joists with a generous overlap where joints occur. Then to compensate for the lack of mass on the ceiling below, screw down our 18mm QuietBoard high density acoustic flooring ensuring the joints are tightly butted. Also ensure the edges where the flooring meets the walls are sealed with Acoustic Sealant.
WALLS AND WINDOWS
As with all studios and home cinemas, windows are not usually required so block up any windows with 30mm of Acoustic Plasterboard and SoundBlocker Membrane. As belt and braces, external shutters could also be fitted and closed and should be heavy and as tightly fitting as possible. Now we will assume the walls are masonry and do not require any additional treatment before we commence with the building a room within a room instructions and for this, we will also assume there is enough ceiling height.
A ROOM WITHIN A ROOM
For this you can use either timber or metal stud and with these you construct a stud wall at least 25mm away from the existing walls. Construct the walls first and it may be easier to build these is sections flat on floor then fit them where required and screwed to the floor but do not forget to allow for the same gap between the top of the stud and the ceiling. It is best to start with two frames in a corner then they will support each other and proceed around the room adding more frames as necessary. Some people like to decouple the frames from the floor by fixing them on top of a resilient foam tape and here it is best to use the 10mm thickness. When all of the stud walls have been fitted, add joists to the top of the frames to support the ceiling. These can be fixed using specially shaped hangers that can be screwed to the side of the stud. It is important that the joists are suitably sized to support the weight of the ceiling according to the overall dimensions of the room so you may have to seek advice on this from a professional builder or structural engineer.
Once the stud walls and ceiling joists have been fitted the voids between can be infilled with AMW of appropriate thickness so if you have used 75mm studs fitted 25mm away from the wall you would require 100mm AMW100 which again should be a loose fit. With the ceiling joists you may wish to use our Wire Netting to help hold the AMW in place. The wire netting is fixed to the underside of the joists then the AMW is fitted on top working across the room adding more netting as required. Alternatively, if you add more Resilient Bars to the underside of the new joists, the AMW can be rested on top. It is often argued that resilient bars added to independent studs do not improve the soundproofing of the structure but feedback we have had from customers would indicate the opposite so will leave it to you to decide to use them or not. If you do, then also fit them to the stud walls so that all the inside faces of plasterboard are decoupled from the frame.
Now the basic room within a room has been completed, you will need to decouple the floor by installing floating floor. This will help stop flanking noise through the floor into other rooms. First loose fit over the floor with our 2mm SBM5 Soundproofing Mat then overlay again with our 10mm R10 resilient insulation. Your new floor can now be installed on top of the R10 and should be QuietBoard fitted with the joints securely glued and with an expansion gap of about 5mm around the edges. This gap can be sealed with our Acoustic Sealant before fitting the skirting boards. The skirting boards when fitted should not come into contact with the new floating floor. More info on how to fit the R10 and floating floor system can be viewed on our web site www.soundservice.co.uk.
Now for the doors and for these you will require two heavy doors fitted with seals to reduce sound leakage around the edges. For best results you can use heavy fire doors fitted with our Acoustic Doorseal Kits or simply fit just one 44dB bespoke Acoustic Doorset that we can supply to your measurements. If fitting the two door option it is best to have one door opening outwards from the room and the door fitted into the new inner room opening inwards as can be seen on our website.
REVERBERATION SOUND AND ABSORPTION
Now that you have built your soundproofed room you will notice that there is a lot of reverberation (echo) and this can spoil your listening or recording pleasure so you will have to install the right amount of sound absorption to cut out standing waves and flutter. If your room has been built with corners that are not 90 degrees then standing waves should not be as much of a problem but for this article, we will assume that all of the corners are 90 degrees. In these corners you will get a build up of low frequency sound so you will need some quite thick sound absorption in those areas and this is where our Acoustic Corner Traps and Cubes can be used. Particularly useful if the room is to be used as a studio. The floor should also be carpeted with a deep pile carpet and felt underlay which leaves the walls and ceiling. You do not want to install too much sound absorption otherwise the room will become too dead so you will have to retain a certain degree of liveliness. As a general rule of thumb, a starting point is to install enough sound absorbing panels equal to the floor area of the room and these can be fitted to the ceilings or walls or both. For the walls we offer a wide range of sound absorbing panels as can be seen on our web site. And likewise there is a choice of sound absorption for ceilings. The most popular panels we supply are Echosorption Plus for the ceilings and Wallsorption for the walls. Wallsorption sound absorbing panels can be supplied in a wide range of colours that can be viewed on our web site so black may be preferred for home cinemas whereas brighter colours could be chosen for studios. I would suggest that a mix of thicknesses are installed so that a greater frequency range will be absorbed so the carpet will be one and you can mix 25mm, 30mm and 50mm for the other surfaces.
If the room is to be used as a studio, you may wish to include different studio sound absorbers that we supply specifically for studios so again, go to our commercial web site www.soundservice.co.uk to view the options we can offer.
Oh and one last thing. Ensure that all lighting is surface mounted. Do not install inset lighting because it will severely affect the performance of the soundproofing you have been trying to achieve.
Hopefully, you are now ready to go but please refer to our web site for more information if you need it and our contact details can also be found there. If you have any difficulty finding or require any more information on how to soundproof a room call us on 01993704981